Exit duct from scrubber

Valves. Butterfly valves are provided at both the inlet, and outlet to each fan. The inlet valves are manually operated, while the. exhaust valves are air operated. The exhaust valves can be sealed airtight to permit repair or removal of the fan without leaksgo. of radioactive air into the Blower and Fan House. It is not necessary to have the inlet valves seal airtight since any leakage is into the system. 

7 Inatrnmentntlon nnd Control. The order of the following description will follow the flow diagrasi shown in Fig. 8.2.A, starting at the off-gas openings in the hoods. 

There is a locally mounted pressure indicator in the off-gas line near each hood. This will inform,the experimenter that there is or is not sufficient static head for him to us e the o.ff-gas opening. 

At the scrubber, instrumentation is included to provide the following operational information  

Static pressure head at inlet of air line to the scrubber  

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In some smelters, a reheater is installed to raise the exit gas above the acid dewpoint (generally 350°-450°F) so the acid remains as a vapor and exits with the gas without adversely affecting the ductwork. Even with a reheater, however, during shutdowns the scrubber entry and exit ducts are subject to chemical attack from acid condensates. 

At the ABCDF, vent gases from the neutralization reactors and the ton container effluent tanks pass through a scrubber, two carbon filters in series, and a fan, prior to entering the HVAC ducts that exit the three toxic/neutralization cubicles. These exhaust HVAC ducts lead to the final banks of activated carbon filters and to the induced draft fans. 

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